Identification of the LH and TSH-secreting cells in the pituitary gland of the rhesus monkey.

Pituitary glands from juvenile (pre-pubertal) and adult male and female rhesus monkeys were examined following immunocytochemical staining with antisera to the beta subunits of ovine luteinizing hormone (LHbeta) and of human thyroid stimulating hormone (TSHbeta). The LHbeta antiserum reacts with a cell that is PAS-positive, occurs singly and is randomly distributed throughout the pars distalis. The diameter of these cells is approximately 11.5 micrometer. They do not seem to vary in number in either juveniles (pre-pubertals) or adults, or in males or females. There appears to be fewer LH cells in the pituitary glands of pregnant and lactating females. In addition to staining cells in the pars distalis, the antiserum also reacts with a population of cells located in the pars tuberalis. The cells that stain with the anti-TSHbeta serum are confined primarily to the pars distalis. They are approximately 15.8 micrometer in diameter and are generally found in groups or clusters located in the anterior and medical regions of the gland. The TSH cells vary in number from one animal to another; however, this variability is unrelated to the age or the sex of the animals. No demonstrable changes occur in the number of TSH cells during pregnancy or lactation.