Spontaneous benign prostatic hyperplasia in the beagle. Age-associated changes in serum hormone levels, and the morphology and secretory function of the canine prostate.

This paper is a cross-sectional study of spontaneous benign prostatic hyperplasia (BPH) in a single canine species. The effects of aging and hormonal changes on the growth, histology, and glandular secretory function of the canine prostate were studied in 42 male beagles ranging in age from 8 mo to 9 yr. The beagle prostate enlarges for at least 6 yr, whether normal or hyperplastic. In contrast, prostatic secretory function, determined by ejaculate volume and total ejaculate protein, declines markedly after 4 yr of age. These reciprocal growth and functional changes in the prostate are closely associated with a progressive increase in the incidence of BPH, which is already apparent in some dogs by age two. With age there is a modest decrease in serum androgen levels with no apparent change in serum 17 beta-estradiol levels. This suggests that the growth and functional changes that are associated with the development of BPH and are initiated very early in life reflect an altered sensitivity of the prostate to serum androgens or a response to the relative decrease in the serum androgen to estrogen ratio.

Testis function in rhesus monkeys treated with a contraceptive steroid formulation.

Rhesus monkeys (Macaca mulatta) were treated with testosterone (100 micrograms/kg/day) plus estradiol (0.5 micrograms/kg/day) via subcutaneous polydimethylsiloxane (PDS;Silastic) implants for thirteen months. This steroid regimen inhibited LH but not FSH secretion by the anterior pituitary, inhibited testicular testosterone and estradiol production and drastically reduced the numbers of vigorously motile spermatozoa in the ejacula. Importantly, these effects on testis function were achieved at dosages of testosterone and estradiol which approximate the amount of these two steroids produced daily in normal rhesus males.

Follicle-stimulating hormone-induced, adenosine 3',5'-monophosphate-mediated movement of immature rat sertoli cells in primary culture.

Sertoli cells dissociated from 10-day-old rat testes form colonies in primary culture in response to FSH. FSH and dibutyryl cAMP stimulated the attachment of Sertoli cells to an equal extent; however, FSH-treated cultures contained a small number of large colonies while dibutyryl cAMP-treated cultures contained a large number of small colonies. This relationship was not altered by the addition of a number of other peptide or steroid hormones. Extracellular cAMP levels and colony density were negatively correlated. Colony size at 24 h of culture was diminished in FSH-treated cultures by the addition of a cAMP antibody at 6 or 12 h of incubation. The addition of cAMP at 24 h to FSH-treated cultures caused a dose-dependent stimulation of colony size but not colony density at 48 h of culture. A point source of cAMP (4 x 10(-3) M in agar) inhibited migration of cells toward the agar spot. An agar spot on the dish substratum containing Sepharose-bound FSH exhibited a halo of cells next to the spot, with a zone lacking cells distal to it. Radioautographs of [125I]iodo-FSH-treated cultures exhibited a nonhomogeneous distribution of silver grains; colony size increased faster than the number of labeled cells. Taken together, the results suggest that 1) FSH is stimulating the attachment of Sertoli cells through an increase in intracellular cAMP, 2) FSH is promoting active aggregation of Sertoli cells in culture through a modulation of extracellular cAMP, and 3) cells with a large amount of bound FSH are acting as centers for aggregation.

Sensitization of bleached Stentor to far UV.

Stentors are more sensitive to far UV-induced delay of oral regeneration following bleaching of their UV-absorbant cortical pigment granules. This finding supports a subcortical location of UV-sensitive sites.