View clinical trials related to Puberty.
Filter by:Hormones are substances that are made by the body and are sent directly out into the bloodstream to increase or decrease the function of certain organs, glands, or other hormones. Testosterone is a hormone found in the blood of all girls, but some girls have too much testosterone in their blood. Too much testosterone in the blood can possibly lead to a problem called polycystic ovary syndrome (PCOS). People with PCOS have abnormal menstrual periods, excess facial and body hair, and too much testosterone in their blood. On the other hand, some girls with too much testosterone in their blood do not develop PCOS. We do not know why some of these girls develop PCOS and why some do not. The purpose of this research study is to find out whether too much testosterone can cause problems with other hormones that can lead to the development of PCOS. This study may help us understand more about the causes of PCOS.
Background: - Researchers want to collect information on diet, physical activity, and sun exposure in children and young adults. The data can provide information on the effect these factors might have on the development of cancer and other diseases. Information collected only from adults does not accurately measure these factors. To collect more accurate information, both mothers and children will provide information. Study participants will be from Hebei province in northeastern China and Jiangsu province in eastern China. Objectives: - To collect and study diet, activity, and sun exposure data from Chinese adolescents and their mothers. Eligibility: - Adolescents between 15 and 17 years of age from Hebei and Jiangsu provinces in China. - Mothers of the study adolescents. Design: - Participants will answer questions about their diet, physical activity, and time in the sun. - Participants will wear a pedometer to measure activity for 7 days. They will also wear a badge to measure sun exposure for 3 days. - Participants will record their activities and food and drinks consumed for 3 days. Urine samples will be collected for a full day. - Participants will have a grip strength test. On the last day of the study, they will provide blood, saliva, and toenail samples. - A smaller separate group of adolescents will provide saliva samples only and complete a food questionnaire.
By clinical examinations and withdrawing of blood samples from a large number of healthy Danish children, this study will reveal if age of pubertal onset is declining. Furthermore, the extensive normative data will provide detailed insight into normal ranges and individual changes of anthropometrics and hormone levels in healthy children during childhood and adolescence.
The purpose of this study is two-fold. (1) We will determine if in mid- to late pubertal girls without hyperandrogenism (HA), progesterone (P4) acutely reduces waking luteinizing hormone (LH) frequency to a greater extent than sleep-associated LH frequency. (2) We will determine if in mid- to late pubertal girls with HA, P4 will acutely suppress waking LH frequency to a lesser degree than it does in girls without HA.