Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1980-3-24
pubmed:abstractText
The concentrations of blood serum steroids from 12 to 450 days old male rats were determined by radioimmunoassay. Testosterone (T) was low (270 pg to less than 1 ng/ml) until day 42; adult levels (3--4 ng/ml) were attained by day 62 and declined tradually with advanced age. 5 alpha-dihydrotestosterone (5 alpha-DHT) did not change markedly (90--160 pg/ml) from prepubertal to advanced age. Except for a small peak on day 22, androstenedione (delta 4 A) levels ranged between 400-500 pg/ml in the adult but declined in older males. Progesterone (delta 4 P) rose steadily to a mean of 5.46 ng/ml at 52 days of age and dropped thereafter. High levels of estrone (268 +/- 38 pg/ml) and estradiol-17 beta (2.76 +/- 0.28 ng/ml) in 12 days old males are in contrast to the low estrogens (20-35 pg/ml) in adult animals. Both T/5 alpha-DHT and total T/estrogen ratios were low before puberty, increased in adults and decreased towards old age. The interplay between gonadotropin and prolactin, which exhibited reciprocal changes in the regulation of steroid production by the gonads with age, are discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Androstenedione, http://linkedlifedata.com/resource/pubmed/chemical/Dehydroepiandrosterone, http://linkedlifedata.com/resource/pubmed/chemical/Dihydrotestosterone, http://linkedlifedata.com/resource/pubmed/chemical/Estradiol, http://linkedlifedata.com/resource/pubmed/chemical/Estrone, http://linkedlifedata.com/resource/pubmed/chemical/Follicle Stimulating Hormone, http://linkedlifedata.com/resource/pubmed/chemical/Gonadal Steroid Hormones, http://linkedlifedata.com/resource/pubmed/chemical/Luteinizing Hormone, http://linkedlifedata.com/resource/pubmed/chemical/Pregnenolone, http://linkedlifedata.com/resource/pubmed/chemical/Progesterone, http://linkedlifedata.com/resource/pubmed/chemical/Prolactin, http://linkedlifedata.com/resource/pubmed/chemical/Testosterone
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0361-073X
pubmed:author
pubmed:issnType
Print
pubmed:volume
5
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
179-94
pubmed:dateRevised
2008-2-25
pubmed:meshHeading
pubmed:year
1979
pubmed:articleTitle
Variations in serum androgens, estrogens, progestins, gonadotropins and prolactin levels in male rats from prepubertal to advanced age.
pubmed:publicationType
Journal Article