A TSH test measures the amount of thyroid stimulating hormone (TSH) in your blood. TSH is produced by the pituitary gland and tells the thyroid gland to make and release the hormones thyroxine (T4) and triiodothyronine (T3). See also: 1  T3 test.  T4 test.
Best Answer: Female cats typically have their first heat around the age of six months, which usually lasts for 5 to 7 days. Cat's heat cycles are light dependent and they usually have heat cycles every 9 to 13 days from January through October, though some indoor cats exposed to constant light times will cycle all year. I advise unless you want kittens to keep her in at these times.
So, how long will a cat remain in heat? Typically, the estrous phase will last between a week and 10 days. However, if your cat isnât able to mate and become pregnant, sheâll very likely go into heat again sometime within the next three weeks.n cats, estrus begins as animals reach sexual maturity, usually at about six months of age, although some cats will go into heat as early as four months and others as late as 10 to 12 months.