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In the male brown-Norway (BN) male rat, reproductive aging is associated with decreased LH-pulse amplitude and area.
J Androl. 1997 Jul-Aug; 18(4):359-65.JA

Abstract

The Brown-Norway (BN) rat has been proposed as a rodent model for the study of human male reproductive aging. As in man, reduction in serum or plasma testosterone (T) and both testicular (primary) and hypothalamic-pituitary (secondary) reproductive dysfunction have been associated with aging in male BN rats. However, the presence of secondary testicular failure in this rodent, as indicated by low serum luteinizing hormone (LH) levels, needs further corroboration. The present study was designed to determine whether age-related differences in the pulsatile patterns of pituitary LH and follicle-stimulating hormone (FSH) secretion occur in gonad-intact male BN rats. Three age groups were examined: young (3-4 months), middle aged (12-13 months), and old (21-22 months). Using intra-atrial cannulae, serial 5-minute blood samples were withdrawn from conscious, unrestrained animals. Plasma LH concentrations were determined by a supersensitive immunofluorometric assay (FIA) and FSH and T by radioimmunoassay (RIA). Mean T levels were different among groups (young > middle age > old). In young rats, T levels were higher in the late morning/early afternoon than in the late afternoon: this variation was not found in older rats. Mean FSH concentrations were higher in the old than in the middle-aged and young rats. Significant differences in mean LH levels were not found among groups. Compared to young rats, shortened pulse interval and reduced area of pulses characterized the secretory pattern of both gonadotropins in old rats. In addition, LH-pulse amplitude and total area of LH pulses were also significantly lower in old than in young rats. Besides the well-recognized primary testicular failure that occurs in the old BN rat, this study confirms a hypothalamic-pituitary deficiency that makes this rodent model ideal for studying human male reproductive aging.

Authors+Show Affiliations

Division of Endocrinology, Harbor-UCLA Medical Center, Torrance 90509, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

9283947

Citation

Bonavera, J J., et al. "In the Male brown-Norway (BN) Male Rat, Reproductive Aging Is Associated With Decreased LH-pulse Amplitude and Area." Journal of Andrology, vol. 18, no. 4, 1997, pp. 359-65.
Bonavera JJ, Swerdloff RS, Leung A, et al. In the male brown-Norway (BN) male rat, reproductive aging is associated with decreased LH-pulse amplitude and area. J Androl. 1997;18(4):359-65.
Bonavera, J. J., Swerdloff, R. S., Leung, A., Lue, Y. H., Baravarian, S., Superlano, L., Sinha-Hikim, A. P., & Wang, C. (1997). In the male brown-Norway (BN) male rat, reproductive aging is associated with decreased LH-pulse amplitude and area. Journal of Andrology, 18(4), 359-65.
Bonavera JJ, et al. In the Male brown-Norway (BN) Male Rat, Reproductive Aging Is Associated With Decreased LH-pulse Amplitude and Area. J Androl. 1997 Jul-Aug;18(4):359-65. PubMed PMID: 9283947.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - In the male brown-Norway (BN) male rat, reproductive aging is associated with decreased LH-pulse amplitude and area. AU - Bonavera,J J, AU - Swerdloff,R S, AU - Leung,A, AU - Lue,Y H, AU - Baravarian,S, AU - Superlano,L, AU - Sinha-Hikim,A P, AU - Wang,C, PY - 1997/7/1/pubmed PY - 1997/7/1/medline PY - 1997/7/1/entrez SP - 359 EP - 65 JF - Journal of andrology JO - J Androl VL - 18 IS - 4 N2 - The Brown-Norway (BN) rat has been proposed as a rodent model for the study of human male reproductive aging. As in man, reduction in serum or plasma testosterone (T) and both testicular (primary) and hypothalamic-pituitary (secondary) reproductive dysfunction have been associated with aging in male BN rats. However, the presence of secondary testicular failure in this rodent, as indicated by low serum luteinizing hormone (LH) levels, needs further corroboration. The present study was designed to determine whether age-related differences in the pulsatile patterns of pituitary LH and follicle-stimulating hormone (FSH) secretion occur in gonad-intact male BN rats. Three age groups were examined: young (3-4 months), middle aged (12-13 months), and old (21-22 months). Using intra-atrial cannulae, serial 5-minute blood samples were withdrawn from conscious, unrestrained animals. Plasma LH concentrations were determined by a supersensitive immunofluorometric assay (FIA) and FSH and T by radioimmunoassay (RIA). Mean T levels were different among groups (young > middle age > old). In young rats, T levels were higher in the late morning/early afternoon than in the late afternoon: this variation was not found in older rats. Mean FSH concentrations were higher in the old than in the middle-aged and young rats. Significant differences in mean LH levels were not found among groups. Compared to young rats, shortened pulse interval and reduced area of pulses characterized the secretory pattern of both gonadotropins in old rats. In addition, LH-pulse amplitude and total area of LH pulses were also significantly lower in old than in young rats. Besides the well-recognized primary testicular failure that occurs in the old BN rat, this study confirms a hypothalamic-pituitary deficiency that makes this rodent model ideal for studying human male reproductive aging. SN - 0196-3635 UR - https://www.unboundmedicine.com/medline/citation/9283947/In_the_male_brown_Norway__BN__male_rat_reproductive_aging_is_associated_with_decreased_LH_pulse_amplitude_and_area_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0196-3635&date=1997&volume=18&issue=4&spage=359 DB - PRIME DP - Unbound Medicine ER -