OBSERVATIONS ON SERUM AND GONAD CHOLESTEROL IN PIGEONS

Abstract

Serum cholesterol of pigeons undergoes a seasonal cycle in concentration with maximal values present in April and minimal values in August. No sex differences were apparent and both sexes exhibited this yearly fluctuation in cholesterol concentration. These seasonal changes occurred even when only males showing histological evidence of spermatogenesis were considered. The suggestion is made that perhaps serum cholesterol is not regulated by the sex steroids in this species. Cholesterol concentration is high in the small undeveloped testis and declines rapidly when gonad development starts. This concentration is inversely proportional to the logarithm of relative testis weight. The logarithm of cholesterol content of the testis is directly related to the logarithm of testis weight. The data suggest that testicular cholesterol is involved in gonad growth and increased mass.