Decreased serum 3,5,3'-triiodothyronine and thyroxine levels accompanying acute and chronic ritalin treatment of developing rats.
Basal serum levels of T3, T4, and TSH and the serum TSH increment after TRH are reported for rats chronically or acutely treated with ritalin. Serum levels of T3 and T4 are significantly reduced in rats chronically treated with ritalin twice daily for 21 days. Female rats appear to be more susceptible than males to the suppressive action of ritalin. Ritalin appears to accelerate the circulatory clearance of serum T3 and T4. Basal serum levels of TSH demonstrate graded elevations after sequentially higher doses of ritalin and, in most cases, hypophyseal responsivity (delta TSH) to TRH challenge appears to be marginally enhanced by chronic ritalin treatment. Thyroidal responsiveness is not adversely affected by chronic ritalin treatment. Serum T3 and T4 levels return to normal levels after chronic ritalin treatment is discontinued; however, the maturational rise of the basal serum level of TSH is permanently depressed in 35 and 100 mg/kg BW ritalin-treated males. Acute administration of ritalin (35 or 100 mg/k BW) results in a significant reduction of the serum levels of T3 and T4 within 5 h and depressed levels persist for 18 days.
D000375:Aging; D000818:Animals; D008297:Male; D008774:Methylphenidate / Q000494:pharmacology*; D009929:Organ Size; D010280:Parathyroid Glands / Q000187:drug effects; D051381:Rats; D013961:Thyroid Gland / Q000187:drug effects; D013965:Thyroidectomy; D013972:Thyrotropin / Q000097:blood; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
D014284:Triiodothyronine; D008774:Methylphenidate; D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin; D013974:Thyroxine