Seasonal variation in plasma LH, FSH, prolactin, and testosterone concentrations in adult male white-tailed deer

Abstract

Blood samples were collected monthly from captive and wild adult (12 months old or older) male white-tailed deer (Odocoileus virginianus) over 1 year in southwest Virginia. Plasma was assayed for luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin (PRL), and testosterone (T) using radioimmunoassays. LH and T levels for the captive and wild deer were essentially similar and followed a distinct annual cycle. LH concentrations (nanograms per millilitre) peaked earlier (October, captive, 4.5 ± 1.8 (mean ± standard error); September, wild, 3.3 ± 0.9) than T concentrations (nanograms per millilitre) (November, captive, 13.3 ± 2.7; November, wild, 23.7 ± 7.8) and dropped off sharply prior to, or concomitant with, T concentrations. LH and T levels were lowest during the late winter and spring. T concentrations were closely correlated with androgen levels (Mirarchi, R. E., P. F. Scanlon, R. L. Kirkpatrick, and C. B. Schreck. J. Wildl. Manage. 41: 178–183 (1977)) determined by competitive protein binding assay. Mean PRL and FSH concentrations in wild and captive deer also displayed seasonal variations. Prolactin concentrations (nanograms per millilitre) were highest in May (147.5 ± 0.0) and lowest in November while FSH levels (nanograms per millilitre) peaked in September (180.2 ± 22.4) and were lowest in March. Differences in hormone concentrations between deer and sheep, and the relationship between PRL and antler growth and FSH and spermatozoan production, are discussed.

Annual Changes in Serum LH and Testosterone Concentrations in Male Sika Deer (Cervus nippon).

“…In the male deer that we used (kept at 4 4°N latitude), serum LH concentra tions increased from spring (March or April), peaked during early summer (June or July), and decreased th ereaft er . Ann ual c hang es in p las ma L H concentrations in temperate cervids (short-day breeders) have been observed in red [10], fallow [11] and white-tailed deer [12,13]. The results of the present study closely agree with the findings of those reports.…”

“…This phenomenon may be partly caused by pulsatile secretion of LH [10][11][12] or the age of stag [14]. However, the annual changes of LH based on the monthly sampling in our data are quite clear.…”

Annual profiles of reproductive hormones in peripheral plasma of the male roe deer (Capreolus capreolus)

“…This indicates modulation of FSH secretion by other factors, such as inhibin, as suggested for the rat (Steinberger & Steinberger, 1976). Lincoln & Short (1980) (Karg & Schams, 1970;Schams & Reinhardt, 1974), rams (Ravault, 1976) and white-tailed deer (Mirarchi, Howland, Scanlon, Kirkpatrick & Sanford, 1978). The prolactin levels increased with increasing daylength and declined with decreasing daylength.…”

Effects of melatonin implants on plasma concentrations of testosterone, thyroxine and prolactin in the male silver fox (Vulpes vulpes)

“…In the silver fox, blue fox and mink, pro¬ lactin rises during the breeding season (Martinet etal, 1981;Maurel et al, 1984;Smith et al, 1985), whereas in the sheep, goat, red deer and white-tailed deer it falls (Pelletier, 1973;Ravault, 1976;Mirarchi et al, 1978;Muduuli et al, 1979;Suttie et al, 1984). It therefore appears as if there is no fixed relationship between the timing of the breeding season and the seasonal prolactin cycle.…”