Biology of Reproduction, Vol 29, 63-71, Copyright © 1983 by Society for the Study of Reproduction

ARTICLES

Effect of pinealectomy on seasonal changes in antler growth and concentrations of testosterone and prolactin in white-tailed deer

DL Snyder, RL Cowan, DR Hagen and BD Schanbacher

A 2-year study was conducted to determine under controlled conditions the role of the pineal gland in regulating the seasonal changes in antler growth and reproduction of male white-tailed deer. Blood samples were drawn from 6 pinealectomized (PX) and 18 control (C) deer at intervals of 2 weeks and analyzed for testosterone (T) and prolactin (Prl). Relative scrotal circumference and main beam antler length were recorded. Relative scrotal circumference was similar in PX and C groups, but the normal pattern was delayed 1 to 3 months in the PX deer relative to the C deer. The mean dates of beginning antler growth, velvet shedding, antler casting and pelage changes were significantly later in both years for PX deer than in C deer. Testosterone concentrations peaked 1 month later in the PX deer than in the C deer for both yearling and 2-year-old deer. Prl concentrations in C deer, but not in PX deer, were correlated highly with day length, and the PX deer were delayed relative to the C deer in showing the normal Prl pattern. Increasing levels of Prl in both groups coincided with beginning antler growth in both years. These results indicate that the pineal gland does not originate the seasonal cycles of male white- tailed deer but may synchronize cycles among individual deer, and regulate the circannual rhythm of Prl concentrations which may in turn influence other hormonal cycles.

This article has been cited by other articles:

				H. Underwood and B. D. Goldman Vertebrate Circadian and Photoperiodic Systems: Role of the Pineal Gland and Melatonin J Biol Rhythms, December 1, 1987; 2(4): 279 - 315. [PDF]